The joint development of the Phase III clinical trial of the heart drug did not reach the primary endpoint, causing the stock prices of Astrazeneca PLC Sponsored ADR (AZN.US) and Ionis (IONS.US) to plummet.

Astrazeneca PLC Sponsored ADR (AZN.US) and Ionis (IONS.US) co-developed an experimental heart disease drug failed to meet the primary efficacy endpoint in the late-stage clinical trials, causing the London-listed stock price to plummet nearly 10% on Wednesday. As of the time of writing, the pre-market stock price of US stocks on Wednesday fell by 8.67%, and Ionis stock price also dropped by over 8%. The Phase III trial, codenamed CARDIO-TTRansform, evaluated the efficacy of Wainua (eplontersen) in patients with transthyretin amyloid cardiomyopathy (ATTR-CM). The results showed that compared to placebo, the drug did not meet the composite endpoint cardiovascular mortality and recurrent cardiovascular clinical events within 140 weeks. Wainua is a monthly RNA-targeted silencing agent that can be self-administered by patients in the US using an auto-injector pen, or administered by healthcare professionals using a prefilled syringe. According to the partnership agreement, Astrazeneca PLC Sponsored ADR and Ionis are jointly responsible for the development and commercialization of Wainua in the US market; outside the US market, Astrazeneca PLC Sponsored ADR holds global exclusive development and commercialization rights. Both companies stated that they will conduct further analysis on the complete dataset to gain a deeper understanding of the trial results, and plan to present the relevant data to the academic community at the European Society of Cardiology (ESC) Annual Congress scheduled for August 2026. Citigroup had previously forecast peak sales of approximately $6.2 billion for Wainua in the ATTR-CM indication, with a 59% probability of success. Some analysts had estimated that the drug could generate sales opportunities of up to $2 billion. The failure of this trial means that this potential blockbuster drug is being removed from Astrazeneca PLC Sponsored ADR's cardiovascular pipeline.